Reviewed by USGSRussia59y ago
M5.5 earthquake 66 km S of Shikotan, Russia
Saturday, February 3, 1968, 11:30:46 UTC · 43.208°N, 146.845°E
A magnitude 5.5 earthquake struck 66 km S of Shikotan, Russia on Saturday, February 3, 1968, 11:30:46 UTC, at a depth of 34.7 km (shallow). It is the strongest earthquake within 300 km since an M5.7 on February 1, 1968.
- Magnitude
- 5.5
- Moderate · mw
- Depth
- 35 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
3 kilotons of TNT
That is about 1/6 of the Hiroshima bomb. It released about 5 times the energy of a magnitude 5.0.
Tectonic setting
70 km
from the nearest mapped plate boundary, between the Okhotsk and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
35 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 75 km
USGS lists 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M6.5 on February 4, 1968. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 264 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.51963 Kuril Islands EarthquakeOctober 13, 1963 · 281 km NE of this epicenter
- 8.31958 Kuril Islands EarthquakeNovember 6, 1958 · 193 km NE of this epicenter
- 8.11952 Tokachi-Oki EarthquakeMarch 4, 1952 · 271 km SW of this epicenter
- 7.542 km SSW of Shikotan, RussiaSeptember 11, 1935 · 30 km NW of this epicenter
- 7.4170 km ESE of Kuril’sk, RussiaFebruary 21, 1937 · 270 km NE of this epicenter
- 7.426 km S of Shikotan, RussiaJanuary 29, 1968 · 41 km N of this epicenter
- 7.3Kuril IslandsApril 5, 1901 · 225 km NE of this epicenter
- 7.2134 km E of Shikotan, RussiaDecember 21, 1946 · 133 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 28 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 80 recorded deaths. The most severe:
- 1843M8.4
Hokkaido: Yezo, Kushiro, Nemuro
25 Apr 1843 · 151 km away
45 deathsModerate damage ($1–5M)tsunami
- 1952M8.1
Hokkaido
4 Mar 1952 · 272 km away · intensity IX
33 deathsSevere damage ($5–24M)tsunami
- 1894M7.9
Off Coast Of Honshu
22 Mar 1894 · 105 km away · intensity IX
1 deathModerate damage ($1–5M)tsunami
- 1938M6.1
E. Hokkaido Island, Japan
28 May 1938 · 210 km away
1 deathLimited damage (under $1M)tsunami
- 1958M8.3
Kuril Islands
6 Nov 1958 · 200 km away · intensity X
Moderate damage ($1–5M)tsunami
- 1963M8.5
Kuril Islands
13 Oct 1963 · 293 km away · intensity IX
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.